1. Field of the Invention
It is well known, the wind energy is obtained through the windmill. When the wind pushes the Paddle Blades, rotates the Wind Wheel around the axis, turning wind energy into mechanical energy. The amount of converted energy is directly proportional to the air density, area that the wind sweeps and square of the wind speed.
Because the wind turbine obtains the energy and decelerates the wind, which leads to some degree limits the wind turbine. German physicist Albert Betz concluded in 1919: regardless of any kind of wind turbine design, the maximum possible output energy of a turbine is 59% of the input energy. Nowadays we can achieve only about 30% of that theoretical efficiency limit of the propeller type turbines in practice. The common efficiency ranges from 1% to 20% for the propeller type turbine, which is about 35% of the vertical axis three-dimensional turbines like Darrieus or Gorlov turbine.
As shown in FIG. 10. (for tradition wind-driven generator only) demonstrates the relationship between the wind speed (frequency) and the energy production (energy). The curves are the Rayleigh distributed for the same average wind speed. Histogram shows the measured data. This curve is a good match for tradition wind-driven generator only, but not for the Portable Wind-driven Alternator.
Because the electrical energy generated is proportional to the square of the wind speed, we can obtain larger amount of energy if we have the greater wind speed. The effective working time only accounts for 15% of the operation time for tradition wind-driven generators, but 100% for Portable Wind-driven Alternator. The Portable Wind-driven Alternators work with the wind speed approximately the same as the speed of vehicles. Example for electrical car: When the electrical car drive 75 mile per hour, the Portable Wind-driven Alternator operates at the wind speed of 33 m/s, the wind pressure is 68 kg per square meter.W0=V2/16 kg/m2)W0—Wind pressureV—Wind speed
Wind Energy rotates the special squirrel cage—Wind Wheel (2), according to the Lever Law, the Wind Energy rotates the Wind Wheel (2) by pushing the Paddle Blades (1) easily, smoothly and in increasing speed; so the Alternator can charge the battery of an electrical car traveling on the way. And then the electrical car will have an extended running time.
2. Description of the Prior Art                Through the study of patents below,        
U.S. PATENT DOCUMENTS6,624,530 B1September 2003Toulon6,897,575 B1May 2005Yu7,105,940 B2September 2006Weesner et al2006/0213697 A1September 2006Sutherland2007/0153537 A1July 2007Scott et al.7,339,286 B1May 2008ChenFOREIGN PATENT DOCUMENTSCA2.296.794July 2001WOWO 03/008223 A1January 2003
We found that all those Portable Wind Power Generator stick to the model of “Horizontal Axle Propeller”, with which can only make out toy-like Portable Wind Power Generator.
The energy obtained by a Wind-driven Alternator is proportional to the area of Air-Intake, and the 3rd power of the wind speed.
The classic formula isPw=½×ρAV3η× 1/102 (kW)Pw—Total powerρ—Air density (kg/m3)A—The area of Air-Intake (sweep area) (m2)v—Wind speed (m/s)η—Efficiency of the alternator (usually equals to 0.4)
From the formula above, we can see that the wind speed and area of Air-Intake are the keys of amount of the total generated power. If the wind speed is fixed, the Air-Intake area of the Wind-driven Generator will determine the output power of the Generator.
So those designs with too small Paddle Blades will have small area of Air-Intake and thus small output power which will make the design useless. However, our invention thoroughly changes the model so that it can output great amount of power and become useful practically.